The invention relates to a method for producing multi-colored, Jacquard-patterned knitted pile fabrics, comprising a ground fabric or warp and a pattern-forming system of pile yarns. For this method, the pattern-forming pile yarns in a knitted pile fabric are attached to the ground fabric preferably in filling pile construction and the non-patterning pile yarns, are held at the ground fabric, the pile yarns are assigned group-wise to each needle wale and, during the knitting process, the pile yarn group can be moved in closed channels of a guide comb in the traverse and racking directions. The selected patterning pile yarns, controlled by means of a non-patterning pile yarn guide, form a shed with the non-patterning pile yarns and are fed by the guide comb in a first course to a pile yarn inlayer for the precise racking for the underlapping. The pile yarn inlayer presses off the underlapped patterning pile yarn during the tying. In the second or returning course, after renewed racking, the patterning pile yarn is also underlapped, tied in, guided back in the channel of the guide comb to the non-patterning pile strand and, after a new patterning pile yarn has been selected, the process of forming the shed is commenced again by the new patterning pile yarn.
The German Democratic Republic patent 242 245 discloses a knitting machine for knitted pile fabrics, which has with a horizontally disposed row of slide needles, with pile sinkers with a filling rigger behind the pile sinkers, and a knitting yarn guide swivelling before the needle head.
The assemblage of pile yarns is arranged in groups and passed through a guide comb in channels. At the same time, the non pile yarns, which are also referred to as non-patterning pile yarns, are guided into a shed plane near the pile sinkers and the patterning pile yarns, at a distance from the pile sinkers, are guided into a second shed plane.
Individually movable non-patterning pile yarn guides, which are known as such and controlled by a Jacquard machine to form a shed, make the shed ready for the independent control of patterning pile and non-patterning pile.
A pile yarn inlayer, which is movable below the sinkers of the guide comb and above the plane of the needles vertically, in the racking direction and also in the longitudinal direction of the needles, has a hook, which is open towards the top and the rear. With that, the pile yarn inlayer takes hold of the patterning pile yarn by means of an appropriate motion and laps the patterning pile yarn under an adjacent needle or over the hook in the first course.
While stitches are being cast off in the first course, the pile yarn inlayer holds the patterning pile yarn and thus also underlaps or overlaps in the second or returning course. When this process is concluded, this pile yarn inlayer releases the patterning pile yarn through an appropriate motion. This patterning pile yarn can now be taken back to the assemblage of the non-patterning piles. A new, patterning pile yarn is selected and brought into the front shed plane to form a shed.
This procedure is very disadvantageous with respect to the performance parameters of the machine.
After the patterning pile yarn is taken hold of by the needle in the second course, the pile yarn inlayer must be aligned initially very precisely in a particular position to the sinkers of the guide comb for returning the patterning pile yarns. This requires much time and entails many uncertainties, because, due to the casting off motion of the needle and the formation of pile loops, significant lateral stress is placed on the patterning pile yarns, particularly in this phase. The pile yarn inlayers and the sinkers of the guide comb are therefore deflected laterally.
The angle of rotation, subsequently available for returning the patterning pile yarn, for the new selection by the Jacquard machine, for the formation of a new shed and for the renewed taking hold of the patterning pile yarn by the pile yarn inlayer up to the racking and underlapping of the patterning pile yarn, is so tightly dimensioned, that an appropriate working speed and, with that, an appropriate productivity of the machine cannot be assured under industrial conditions.
Aside from the patent mentioned, other patents describe a large number of very similar variations of the method for selecting and tying in patterning piles and non-patterning piles during the production of Jacquard-patterned, knitted pile fabrics. By way of example, reference is made here to the German Democratic Republic patents (DD) 140 767, 153 399, 207 941 and 136 986.
For all the methods presented in the prior art, the same negative phenomena with respect to the concentration of functionally important movements of the stitch-forming elements in a narrowly limited angular region occur.
To improve the combined action between the sinkers of the guide comb and the pile yarn inlayer, the latter was provided with an upwardly directed projection, which remained constantly in engagement with the second channel of the guide comb (DD patent 156 330). With that, a frequently desired, mutually independent racking of guide comb and pile yarn inlayer is sacrificed for functional reasons.
The production of a knitted pile fabric, for example, by the method of the patent 207 941, admittedly was possible in principle with a method thus limited and with such an apparatus. However, the productivity of the pile knitting machine remained greatly limited. Especially with larger working widths of up to 4 meters, neither the method nor the apparatus is usable.
There are special problems with the known methods especially when the patterning pile yarns are attached to the foundation fabrics in the pile material-saving filling construction. The reason for this lies therein that, in the case of the above method, the newly selected pile yarn is racked at a very early point in time in the first course following the selection process and must be brought into the underlapping position.